Knockdown scaffold



June 8, 1954 c. F. MARONEY ET A1. 2,680,655

KNocKDowN scAFFoLD Filed Dec. 6, 1949 diie/wey.

Patented June 8, 1954 KNOCKDOWN SCAFFOLD Clair F. Maroney, Ralph W. McGrew, and Daniel I. Weisz, Ellwood City, Pa., assignors to Beaver Art Metal Corporation, Ellwood City, Pa., a corporation of Pennsylvania Application December 6, 1949, Serial No. 131,428

9 Claims.

This invention relates generally to knock-down scaffolds and, in particular, to an improvement on the connections shown in Patent No. 2,435,171 and Patent No. 2,483,862 for securing the diagonal braces or stays to the spaced rectangular end frames of such scaffolds in order to form a rigid self-sustaining structure.

Knock-down scaffolds are used extensively but as made prior to the invention covered by patents aforesaid, they required considerable time and labor as well as the use of tools for erection and dismantling. It is the object of this invention to provide a connection between the braces and end frames even simpler and easier to manipulate than the type shown in said patents.

In a preferred embodiment of the present invention there are provided gusset plates at the junction of the horizontal and vertical members of the end frames. These plates have slots extending thereinto from the exposed edge, adapted to receive the end of a brace or stay. The brace is provided with a head at each end and a flange spaced inwardly thereof. The head is preferably of square cross section. Between each head and flange there is an end portion of substantially square cross section adapted to t snugly within the slot in the gusset plate. A gravity latch or locking member which may be in the form of a hook is pivoted to the gusset plate so as to engage an edge of the head of the brace when the end portion is inserted into the slot in the gusset plate.

A more complete understanding of the invention may be obtained from the accompanying drawings which illustrate two preferred embodiments of the invention.

In the drawings,

Figure 1 is a section through the horizontal members of one end'frame of a scaffold showing the ends of diagonal braces secured thereto.

Figure 2 is a section on the line 2-2 of Figure 1.

Figure 3 is a partial elevation of one end frame of a scaffold having the invention applied thereto.

Figure 4 is a section through the horizontal members of one end frame of a scaifold showing the ends of diagonal braces secured thereto by a different embodiment of the invention.

Figure 5 is a section on the line 5-5 of Figure 4.

Figure 6 is an elevational view of the locking pin of this second embodiment.

Referring first to Figures 1 through 3, there is illustrated end frames I0 composed of posts II and beams I2 welded together. The posts and beams are shown as tubular but they may be of any section.

In erecting the scaifold, the end frames are set up in spaced relation and connected by diagonal braces or stays I3. The braces may also be of any desired section but are shown as tubular. The frames are built up one on another to the desired height, dowels I4 being inserted in the upper ends of the posts ofeach frame and the lower ends of the posts of the next frame above are disposed thereon. The improved connection of this invention includes gusset plates I5 preferably of U-shape as shown in Figure 1, welded to the posts and beams in the corners of the frames and having slots I6 therein. Each slot has substantially parallel sides extending from the exposed edge of the plate and terminating at a point spaced from the edge. As shown in Figure 1, there are two gusset plates in each corner of the frame, the two plates being disposed parallel to each other forming wings of a substantially U-shaped member.

Each brace has a head IT in the form of a square welded or otherwise for-med on each end thereof. A flange I8 is welded at each end of the brace a short distance inwardly of the head. A square end portion I9 between the head I 'I and flange I8 is formed on the brace such that the length of its sides is substantially equal to the width of the slot I6 in the gusset plate so that the end portion I9 will make a snug nt in the slot I6, thereby preventing rotation of the brace in the slot. A gravity locking member 20 is pivoted on the gusset plate I5 above the slot I6. The locking member 2i! has an inclined portion 2| and hook portion 22 adapted to fall behind the edge of the head I1 (see Figure 2). Apin 23 supports the end of the locking member 2D, to prevent its falling below the slot I6.

It will be apparent from the foregoing that the braces may be quickly and easily connected to the gusset plates. The end portion I9 of the brace is slid into the slot I6 whereupon the head I1 strikes the inclined portion 2| of the locking member 20 which slides across the edge of the head until the end portion I9 reaches the end of the slot I5 at which point the hook portion 22 drops behind the head IT. This locks the brace I3 in position in the slot IB, thus rmly connecting the braces to the end frames and constituting the latter a rigid self-sustaining structure.

When it is desired to dismantle the scaffold, the end frames may be disconnected and taken down by removing the ends of the braces from the slots in the gusset plates. This is accomplisher by lifting the locking member 26 to disengage the hook portion 22 from the head Il' of the brace and withdrawing the end portion i9 of the brace from the slot i6.

Figures 4, 5, and f6 show `a slightlyvdiierent form lof locking arrangement. The gusset plate 26 is of U-shape having spaced parallel sides in which slots 25 are formed. The braces i3 cooperating therewith are identical with those described above excepting that a notch 26 is cut in at least one edge of the head i? intermediate its ends. A downwardly Ycurved aperture 21 is cut in each side of the gusset plate 24 above 'the slots 25 terminating adjacent the upper edge of the slot. A locking pin 23 is slidably mounted in these apertures so as to engage the notches 26 in the heads il of two opposite braces I3.

The function of the various parts of the two embodiments is the same with the exception of the locking members.

In each case, however, the locking members operate by gravity .to engage the head of the brace so as to prevent its removal from the slot in the gusset plate.

The connection of this invention is characterized by numerous advantages. It is simple, therefore cheaply manufactured. It is easy to operate, requiring no skill or experience. The use of tools is entirely eliminated, while at the same time the connection is strong and tight and not likely to be accidentally disconnected.

The only working part, the locking member, is permanently united with the gussetplate on the end frame so that it cannot be detached, lost, or misplaced.

Although we have shown and described only two forms of our invention, it will be understood Ythat it may be otherwise embodied within the scope of the following claims.

`We claim:

l. Aiseparable connection for securing diagonal braces to the rectangular end yframes of a knock-down scanold comprising at least one gussetplate on-the end frame having a substantially rectangular slot therein, a cuadrangular end portion on the brace adapted to enter the slot,.said end portion being substantially equal in thickness to the width of the slot whereby to engage the edges thereof to prevent rotation of the end .i

portion in the slot, retaining means integral with the brace on either side of the-end portion whereby the end portion is retained against longitudinal movement within the slot, gravity 'locking means Aon the gusset plate, and engaging means on at least one of the retaining means cooperating with the gravity locking means to hold the brace against removal from the slot.

2. A connection as dened by claim 1 characterize'd by a pair 'of gussets in each'corner of i down scalold comprising a pair of gusset plates in each corner of said frame, each of said gusset plates being parallel to the other, a substantially rectangular slot in each gusset plate, a quadrangular end portion on the braces adapted to enter a slot, said end portion being substantially equal in :thickness to thewvidth'of the slot whereby to engage the edges 4thereof to prevent rotation of the end portion in the slot, retaining means integral with the brace on either side of the end portion whereby the end portion is retained against longitudinal movement within the slot, gravity 'locking means on the gusset plate,

:and engaging means on at least one of the retaining means cooperating with the gravity locking'means to hold the brace against removal from the slot.

5. A connection as deiinecl by claim 1 characterized by said gravity locking means being a hook pivoteol to the gusset plate and adapted to drop behind-one of the retaining means when the end portion of the brace is linserted into theslot.

6. A connection as deiined inclaim l characterizedbythe retaining meansand the end portionbeingquadrangular in cross section, said end portion having one dimensionisubstantially equal to the width of the slot.

7. Av connection as delined -in claim 1 characterized by the slot having parallel sides andthe lend portion of the brace being quadrangular in cross section Vhaving .one dimension substantial- 4or the slot and a vnotch in at least one retaining means engaged by the pin when said pin is at the lower terminus of theaperture.

9. A connection vas deinedfby claim 3-characterized `by said gravity locking means being a v pin slidable in generally vertical-'apertures in the parallel gusset plates-saidapertures terminating :adjacent the upperedge of the slot, and atnotch in at least one retaining means of -each :brace engaged by the pin when said pin is substantially at the-bottom of the apertures.

-References-Citedin the file of vthis patent UNITED STATESPATENTS Number Name Date 376,794 Barns Jan."24, '1886 377,966 Tlley Feb.`14, 1888 427,180 'MacLaurin May', 189D 744,194 Harrison Nov. 17,1903

2,246,457 Schultz VJune 17, '1941 2,372,603 Kennedy Marq20, `1945 2,386,710 Pancoeet al, Oct.'9, 1945 2,472,423 Hawes June '7, 1949 2,483,862 Weisz Oct.4, `1949 .FOREIGN PATENTS Number Country Date 661,528 Germany June `20, v1938 

